ghost

Ghost is a command-line app that can be used to provide auto-compile and hosting functionality, depending on configuration. It was written in and for the Go language, but should be general enough to use in other contexts.

to use

From a command prompt, navigate to the ghost directory and launch the app with at least one argument, the path to a configuration file. The config file will determine how the app works. There are currently three supplied default config files:

1. host
   Host mode launches an application and keeps it running.
   example (on windows): ghost.exe host -file=notepad.exe
   
2. gulp
   Gulp mode watches a folder. When a change is detected, it builds the application and then launches it in host mode. The supplied configuration file is used explicitly to gulp Go applications.
   example: ghost.exe go_gulp -watch="C:\go\github.com\hackborn\ghost" -run="ghost.exe"
   (don't try this exact example, it will just recursively launch ghost)
   or example for a project where the main.go is in a subfolder called main:
   ghost.exe go_gulp -watch="C:\go\github.com\hackborn\server" -build="main" -run="server.exe"
   
3. format gulp
   Format gulp works like gulp mode, but if formats the Go code before building it.
   example: ghost.exe go_fmt_gulp -watch="C:\go\github.com\hackborn\ghost" -run="ghost.exe"
   

The default configuration files are currently found in data/graphs/. If that folder doesn't exist relative to ghost.exe then it won't find any config file.

Alternatively, you can specify an absolute path to a custom configuration file, i.e. ghost.exe path\to\file.xml. Look at the included config files for examples, and see a complete description of the format at https://github.com/hackborn/ghost/blob/master/docs/example_graph.xml

design

At heart it's a simple pipeline processor, where the pipeline is composed of any number of nodes run in series. There are currently two types of nodes: Watch, which fires a message in response to changes in a folder tree; and Exec, which runs a command. There's an additional node called Host, which is actually an Exec node configured to automatically run and rerun the Exec command.

Each node runs one or more gofunctions and communicates via channels. The graph processing is not tied to any sort of loop, since either a node will autorun once the graph is started, or nodes will be fired in response to a file change.

known issues

• The watcher will not add or remove folders from the watch list. You can add or remove files to watch folders, but if you add a new folder you want watched, you need to restart the app.
• Watcher has no way to disallow folders, it currently attempts to watch every folder under the root. The number of folders to watched is managed by having a filter, but if you don't include the filter, and have a large directory structure of files you don't care about, you end up with a large number of watched folders.
• The exec command will not run if it receives continuous messages from a watch. This needs to be improved a little so it always runs after a set time, even if there are more changes.
• App does not properly shut down when hitting the close button on a windows command prompt. Not sure if this impacts anything -- go seems to be cleaning up all the important parts.

acknowledgements

Much thanks to the fsnotify project -- https://github.com/fsnotify/fsnotify